Contact electrification is a phenomenon in which surfaces become charged when they are brought into contact and are then separated. While this is required in some applications, many a times it poses to be an undesirable effect. For example, charge accumulated on solid surfaces by contact electrification can cause slight annoyances in many everyday activities, such as the sticking of clothes onto each other while drying, the experience of a shock when one touches a doorknob in dry weather, and the adhesion of dust particles on surfaces (e.g., on screens of computers due to attractive electrostatic force). More importantly, electrical discharges (e.g., sparks) due to the accumulated charge may potentially result in dangerous situations such as the explosion of flammable gases, dusts, and organic liquids (e.g., during the fueling of vehicles). Electrical discharges are also responsible for the damage of equipment; these damages are reported to cost the electronic industry billions of dollars per year. In many other types of industries, the accumulation of charge on solid surfaces also can make processes less efficient. For example, charged particles that adhere onto the walls of reactor vessels can hinder effective heat transfer; charged powder in the pharmaceutical industry can lead to non-uniform blending, thus resulting in non-uniform dosages of the products. Therefore, it is important to eliminate charge on solid surfaces due to contact electrification.
Polymers are especially problematic: they have the natural tendency to charge highly on contact, and are typically insulating. The approach to eliminate static charge involves making the polymers conductive in order to dissipate charge away from their surfaces. Methods include fabricating polymeric composite materials (with a conductive material), doping (e.g., doped conjugated polymers), or adding antistatic agents. A wide variety of antistatic agents has been developed, such as powdered metals, carbon nanotubes, and graphene. In general, these methods have their disadvantages and limitations. For example, modifying the materials (e.g., through doping or adding antistatic agents) may change their properties in unfavourable ways such as by reducing their mechanical strength, or changing their colour. They may also become incompatible with certain applications; for example, the materials may become corrosive, toxic, or instable to heat. In order to preserve the properties of the materials, one approach is to coat their surfaces with a layer of conductive film. Other methods include coating surfaces with charged molecules (e.g., self-assembled monolayer of ionic molecules, and multilayers of polyelectrolytes).
Such chemical modification and coatings of the surface, however, are susceptible to degradation through wear and tear, and may require additional considerations. For example, if a certain region has worn off to a certain extent such that a region becomes electrically insulated from ground, the whole region loses its ability to conduct charge away.
There is therefore a need for an improved material.